Inner sactum oil galley plug

Okay I have gone back to 1979 Dodge Sportsman Plymouth Voyager Vans and front suspension chassis book service manual, page 9 - 49 and figure 53 it says that if this plug is not replaced that it will cause erratic, low or no oil pressure.
Then I went to my 1988 Dakota service manual page 9.34 oil line plug figure 57 is on page 9.31 it says the oil plug in the location in the vertical passage in the block between the oil to filter and the oil from filter Passage. Missinstallation or absence could cause erratic, low or no oil pressure.
I have also seen this very same thing said in the how to build big inch small block Mopars so I truly do not believe that it was a misprint from Ma Mopar. Sorry boys and girls that just don't fly. Thank you very much for your time and interest.